The present invention relates to a so-called leaf-type digital clock (e.g. in U.S. Pat. No. 3,220,174) in which a plurality of tilting leaf-plates carrying figures and the like are hinged on the peripheries of horizontally oriented frames and shown in individually separated windows on the front surface of the clock.
In the leaf-type clock, there are advantages that the figures and letters to be indicated can be made much larger in comparison with those of the other kinds of digital-type clocks, in which hours, minutes and the like are marked on the cylindrical surface of drums, and further that even continuous sixty figures of minutes or thirty-one figures of dates can be indicated with only one rotary frame.
On the other hand, in such leaf-type clock, a great many sheets of leaves are needed for hour- and minute-indications in total, that is, 108 sheets of leaves at least. Then, when the minute indicating leaf is so constructed as it is divided into two kinds of parts, that is, ten-minute indicating leaf and one-minute indicating leaf while providing an AM-PM indicating mean thereto, it is estimated that only 34 sheets of leaves in total will serve for hour- and minute-indications. However, when such a division of minute-indicating leaf as above is applied to the conventional leaf-type clock which has been driven by gear train with uniform rotation, there will be caused a fatal disadvantage that it takes many minutes, after a leaf has been turned over, to make the next leaf vertical to observer's eye, for example, it takes 60 seconds for a one-minute indicating leaf, 10 minutes for a 10-minute indicating leaf and 60 minutes for an hour indicating leaf.